Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C5/00—Disposition of burners with respect to the combustion chamber or to one another; Mounting of burners in combustion apparatus
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/32—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid using a mixture of gaseous fuel and pure oxygen or oxygen-enriched air
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C6/00—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion
  • F23C6/04—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection
  • F23C6/045—Combustion apparatus characterised by the combination of two or more combustion chambers or combustion zones, e.g. for staged combustion in series connection with staged combustion in a single enclosure
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
  • F23D11/10—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space the spraying being induced by a gaseous medium, e.g. water vapour
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/20—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone
  • F23D14/22—Non-premix gas burners, i.e. in which gaseous fuel is mixed with combustion air on arrival at the combustion zone with separate air and gas feed ducts, e.g. with ducts running parallel or crossing each other
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/46—Details, e.g. noise reduction means
  • F23D14/72—Safety devices, e.g. operative in case of failure of gas supply
  • F23D14/78—Cooling burner parts
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D17/00—Burners for combustion conjointly or alternatively of gaseous or liquid or pulverulent fuel
  • F23D17/002—Burners for combustion conjointly or alternatively of gaseous or liquid or pulverulent fuel gaseous or liquid fuel
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23Q—IGNITION; EXTINGUISHING-DEVICES
  • F23Q9/00—Pilot flame igniters
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C2201/00—Staged combustion
  • F23C2201/20—Burner staging
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
  • F23D2900/00004—Burners specially adapted for generating high luminous flames, e.g. yellow for fuel-rich mixtures
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
  • F23G2209/00—Specific waste
  • F23G2209/10—Liquid waste
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
  • F23L2900/00—Special arrangements for supplying or treating air or oxidant for combustion; Injecting inert gas, water or steam into the combustion chamber
  • F23L2900/07005—Injecting pure oxygen or oxygen enriched air
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E20/00—Combustion technologies with mitigation potential
  • Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

Definitions

• This invention relates to methods and apparatus for generating highly luminous high temperature, low NO x flames using fluid fuels.
• the methods and apparatus disclosed may be used as the major source of energy and also as an assisting energy source in melting furnaces, industrial heating and heat treating furnaces, kilns, incinerators and other high temperature applications.
• Utilization of oxygen to increase the heating efficiency due to higher flame temperature and the lower volume of flue gases is a well-known combustion approach.
• known methods of introduction of the oxygen into a combustion process through the injection of oxygen into the combustion air commonly called oxygen enrichment, result in even further reduction of flame luminosity and an increase of N0 X emissions due to oxidation of nitrogen with oxygen inside the higher temperature flame.
• the ratio control between fuel flow and enriched air flow is similar to standard fuel/air ratio control.
• the ratio of total air to total oxygen is normally constant during the heating cycle.
• U. S. Patent No. 3,729,285 to Schwedersky discloses a staged method of gaseous fuel combustion inside the burner tunnel wherein two fuel streams with associated air streams are separately controlled, delivered to the combustion chamber and burned prior to mixing the combustion products together to create a low N0 X flame.
• the ratio of oxidizer to fuel would have to be at least 75% of stoichiometric to insure adequate heat release during the partial combustion of the fuel being pyrolyzed, since heat stored in the N2 molecules in the pyrolysis zone will be unavailable for pyrolysis.
• This diluted flame core reduces flame temperature inside said core, and also has a relatively low air deficiency, eliminating the possibility of significant formation of carbon microparticles of the proper size required to provide adequate flame luminosity.
• this invention cannot practically utilize pyrolysis. since most fuel is used to create heat, leaving little fuel to be pyrolyzed.
• Carbon microparticles required for maximum emissivity are in the size range of 0.05 to 4.0 microns and the formation of particles in this size range has been shown to be optimized at above 3000°F, which is a temperature that is not achievable without a high concentration of oxygen in the oxidizing gas.
• 3000°F is a temperature that is not achievable without a high concentration of oxygen in the oxidizing gas.
• a low flame core temperature significantly reduces the radiative capability of said particles.
• the flame introduced by the Schwedersky patent has less N0 X emissions than other flames, but it also has low radiative heat flux due to the low temperature of the flame envelope.
• the ratio of total oxygen to total fuel is not variable in such systems, the volume of flue gases per Btu at standard conditions is fixed throughout the entire firing cycle.
• the temperature inside the refractory combustion chamber is slightly reduced due to staged combustion.
• the Schwedersky Patent also describes a burner utilizing more than one oxidizing stream to stage combustion, but does not have the ability to utilize pure oxygen, as is made clear by the fact that metal as used in the combustion chamber could not survive the temperature of a flame utilizing pure oxygen, nor does it disclose enrichment by or use of pure oxygen. Disclosure of the Invention
• the process is comprised of the initial control of fuel, oxygen and air flows, delivering the oxidizers to a burner as two oxidizing gases having different oxygen concentrations (for example, pure oxygen and air, or oxygen and oxygen enriched air).
• a first oxidizing gas containing a high oxygen concentration is injected as a stream into the central zone of a combustion tunnel (or combustion chamber), and part of the fuel (preferably the major part) is injected into said central pyrolysis zone to mix with said first oxidizing gas (preferably at ratios of fuel to oxygen between 0.8 - 2.5) to create a highly luminous, high temperature flame core containing microparticles of carbon of the proper size for maximum luminosity and high temperature, and a relatively small amount of hydrocarbon radicals.
• part of the fuel (preferably the minor part) is injected in a plurality of streams about said flame core to mix with a second oxidizing gas (containing a lower oxygen concentration than the first oxidizing gas) and injecting said second oxidizing mixture about said flame core and said minor fuel flow to mix with said minor fuel flow (preferably at fuel to oxygen ratio below 0.4).
• a second oxidizing gas containing a lower oxygen concentration than the first oxidizing gas
• injecting said second oxidizing mixture about said flame core and said minor fuel flow to mix with said minor fuel flow (preferably at fuel to oxygen ratio below 0.4).
• the utilization of a high oxygen concentration in the first oxidizing gas makes it possible to boost the temperature of carbon microparticles and the concentration of these particles (due to low flue gas volume), thus significantly increasing the radiative flux from the final flame toward the product being heated.
• the additional heat flux of the highly luminous flame results in reduction of the temperature of the products of combustion prior to their contact with the furnace load, which will reduce the oxidation of the load. Therefore, a larger portion of the heat released by combustion may be transferred to the load at a given process temperature due to the higher temperature and luminosity of the flame envelope being produced by the above described simultaneously occurring parallel stage combustion.
• the low NO x produced by this combustion method is due to the very low nitrogen concentration of the first oxidizing gas (preferably pure oxygen) present inside the flame core where the high concentration of CO and hydrocarbons also prevents nitrogen oxidation.
• the plurality of fuel lean flames diluted, for example, with excess of C>2 and N2 surrounding said central flame core do not have a large enough flame pattern to raise the temperature inside their individual flame cores above 2700°F and thus to trigger N0 X formation.
• a single fuel source may supply the fuel for both the central fuel-rich and outer fuel-lean flames or mixtures.
• the fuel may be introduced through two separately directed nozzle sets, one part being directed to mix with the central flame core, and the other part to mix with the second oxidizing gas surrounding said central zone.
• the dimensions of the openings introducing the fuel streams and their directions determine their relative volume and the intensity of mixing with the oxidizer.
• the flame velocity, temperature, and combustion product volume may be varied, for example, at a given heat energy input level through the adjustment of the ratio between air and oxygen in the oxidizing gases, constantly keeping the two fuel flows at a fixed ratio.
• Fuel for example, natural gas
• Fuel may also be supplied to the burner as two separate streams and in such case the flame characteristics may be varied by separate control of the fuel flows delivered to the burner by separate conduits.
• two different fuels may be used for combustion simultaneously.
• liquid fuel may be used in central pyrolysis zone and coke oven gas or natural gas in minor fuel flow peripheral zone.
• the participation of oxygen should be lower than that required for complete pyrolysis of the fuel.
• the pure oxygen supplied for participation in the combustion process is reduced, for example, to a ratio of pure oxygen/air below 0.2.
• the energy balance in the pyrolytic zone may become critical and to support adequate temperature conditions in the pyrolytic zone more fuel is directed to the fuel lean zone, thereby reducing the amount of fuel being pyrolyzed so as to increase the temperature in the pyrolytic zone as well as in the surrounding zone occupied by the fuel lean flames.
• the present invention may be used in a broad range of applications where a highly radiative flame is desirable.
• the high radiation flux from the pyrolytic zone may raise the temperature inside the combustion chamber to a level where the exposed metal parts inside the combustion chamber will deteriorate. Therefore, liquid cooling of burner parts so exposed may be necessary in certain embodiments of the present invention.
• the burner and method of combustion may also be used for incineration of fluid hazardous waste having high or low caloric value.
• liquid waste may be introduced instead of one of the fuel streams, preferably the central stream.
• Oxygen utilization in this case makes the flame pattern hotter and the oxidizing gas more oxygen concentrated, thus improving the thermal destruction efficiency of the flame pattern. Utilization of this approach for low caloric value fuels, such as landfill gas, has similar advantages.
• Fig. 1 is a side section view through the center of a burner of a first embodiment of the present invention.
• Fig. 2 is a section taken along line 2-2 of Fig. 1.
• Fig. 3 is a section taken along line 3-3 of Fig. 1.
• Fig. 4 is a side section view of the burner of a second embodiment of the present invention.
• Fig. 5 is a side section view through the center of a burner of a third embodiment of the present invention.
• Fig. 6 is a side section view through the center of a burner of a fourth embodiment of the present invention.
• Fig. 1 shows details of a preferred embodiment of the invention.
• the burner 10 comprises a nozzle assembly 11 which includes ports which direct streams of oxidizer gases and fuel into the combustion chamber 12 for combustion.
• the combustion chamber 12 in Fig. 1 may be within the wall of the furnace or other apparatus for industrial heating.
• a high oxygen concentration oxidizer is introduced through central port 13, along the center line of the combustion chamber 12.
• pure oxygen or an oxidizing gas containing a higher percentage of oxygen than in air is directed through central tube 14 to port 13.
• Air or an oxidizing gas having a lower oxygen concentration than the first oxidizer is introduced into the combustion chamber as a second oxidizer stream from air inlet 15 through air inlet port 16, of which there are eight in this embodiment.
• the air inlet ports 16 are directed about the central axis of the combustion chamber 12 to promote vigorous mixing of the second oxidizing gas with the fuel.
• the air inlet passages may include insulation 17 when a preheated second oxidizer gas is used.
• Fluid fuel such as natural gas
• Fuel ports 19 of which there are four in this embodiment, are used to introduce streams of the major portion of the fuel toward the first oxidizer to provide vigorous mixing.
• the ports 20 for the minor fuel flow serve to direct the minor flow of the fuel toward the lower oxygen concentration second oxidizer streams from ports 16.
• the minor fuel ports 20 will have a smaller cross-section area than ports 19, such that the relative volumes of fuel directed to each oxidizer stream is automatically controlled.
• the minor fuel ports 20 are parallel to the center line of the burner.
• a hot center core comprised of an oxidizer containing a high O2 concentration and having a rich fuel/oxidizer ratio, surrounded by a lean fuel/oxidizer mixture comprising an oxidizer containing a lower O2 concentration mixed with said minor fuel flows.
• Fig. 2 is a cross-section through the various oxidizer and fuel inlet passages.
• the passages are concentric tubes, with inner inlet tube 14 being the high concentration oxidizer supply, middle tube 18 being the fuel supply, and outer tube 15 being the air supply, as discussed above.
• Fig. 3 shows a cross-section through the burner face 11 showing the location and relative size of the various ports described above.
• Fig. 4 shows an alternative embodiment of the burner face which includes water cooling.
• water cooling of the burner assembly may be necessary. This is shown in Fig. 4 by a water cooling inlet 25 communicating with a water cooling outlet 26. Proper circulation of the water is arranged by appropriate baffles within the nozzle assembly 11.
• an embodiment of the burner includes a full water cooled combustion tunnel 30, appropriate when an extremely hot high velocity flame is created within the combustion chamber or when the furnace on which the unit is installed can transfer a significant amount of heat back to the burner. Additional features of this embodiment shown in this figure are the water jacket 31 of the combustion tunnel 30, the cooling baffle bypass hole 32, a flame detector channel 33, and a spark plug 34 for ignition.
• the water cooled nozzle 35 is provided to choke the hot flame generated by the burner to create high velocity. Otherwise the burner is similar to the other configurations previously described.
• FIG. 6 an embodiment of a dual fuel burner design using air preheat is shown.
• This variation provides the ability to fire fuel oil or other liquids.
• oil is introduced through the tube 40, while atomizing gas enters through another tube 41.
• the oil and atomizing gas flow through the atomizing nozzle 42, which is cooled by contact with the heat conducting burner plate 43, which is in turn cooled by contact with cooling water jacket 44.
• the conically shaped oil nozzle 42 and attached tubes 40 and 41 can be removed from the rear of the burner for service and inspection.
• Oxygen enters through ports 50 which are directed towards the center line of the burner.
• the oxygen is provided to ports 50 through inlet tube 47.
• Gas, or other fuel in introduced in inlet 48 to fuel ports 51 which are parallel to the center line of the burner and further away from the center line than oxygen ports 50.
• Air which may be preheated, is introduced in inlet 15 and into the burner through ports 16, which direct the air towards the gas within the combustion chamber to form the outer flame cores.
• Insulation 45 may be provided around the center section of burner to prevent heat loss from preheated air due to contact with the cooling water jacket.
• An internal bleeding path 46 is provided between inlet tube 47 and inlet 15 for directing some of the pure oxygen into the heated air for oxygen enrichment of the air.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Manufacture, Treatment Of Glass Fibers (AREA)

Priority Applications (1)

Applications Claiming Priority (1)

Publications (3)

Family

ID=22208891

Family Applications (1)

Country Status (7)

Cited By (1)

Families Citing this family (28)

Citations (6)

Family Cites Families (5)

• 1988
  • 1988-09-02 WO PCT/US1988/003047 patent/WO1990002907A1/en active IP Right Grant
  • 1988-09-02 EP EP88908893A patent/EP0432153B1/de not_active Expired - Lifetime
  • 1988-09-02 AU AU25378/88A patent/AU644350B2/en not_active Ceased
  • 1988-09-02 BR BR888807917A patent/BR8807917A/pt not_active IP Right Cessation
  • 1988-09-02 JP JP63508204A patent/JPH04500265A/ja active Pending
  • 1988-09-02 DE DE3852651T patent/DE3852651T2/de not_active Expired - Lifetime
  • 1988-09-02 KR KR1019900700924A patent/KR0152648B1/ko not_active IP Right Cessation

Patent Citations (6)

Non-Patent Citations (3)

Also Published As

Similar Documents

Legal Events